1. Field of the Invention
The invention relates to a method for metallically connecting the faces of rods, optionally of profiled rods, e.g., rails, with great longitudinal extension, directed to friction welding.
2. Discussion of Background Information
In principle, fusion-welding methods and hot-pressure welding methods, namely friction welding methods can be used to connect the ends of rods. In assembly technology, friction welding methods can have economic and qualitative advantages; however, experts think their use is not expedient for some types of joints, e.g., joining the faces of profiled rods.
With friction welding of parts, two surfaces to be joined are pressed together and moved relative to one another, whereby frictional heat is generated and the part areas are heated. Through the heating of the areas near to the friction surfaces, a plasticilation of the material therein occurs, so that after the completion of the relative movement and an increased pressing apart of the parts, a metallic connection occurs through solid diffusion.
If it can be done at all, rods with great longitudinal extension and rods profiled in cross section can be produced axially aligned only with extraordinary effort directed to a rotational friction welding method, whereas a profile-aligned connection is an unsolved problem.
With a connection of the rods by a linear friction welding or an orbital friction welding, it is important to achieve a precise axially aligned alignment of the same in the connection area. In particular with a friction welding of profiled rods, such as rails, it is additionally of greatest importance to connect the cross-sectional surfaces with precision fit.
A method and a device for the friction welding of railway rails and comparable, similar carrier profiles is known from DE 19807457 A1, in which an intermediate piece is moved in linear or orbital oscillation between the rail ends to be connected and the rail ends are pressed toward one another onto the intermediate piece in order to generate the heat necessary for welding through frictional heat. Such a friction welding method has the advantage that an axial alignment of the stationary rails during friction welding can be achieved irrespective of the method; however, a formation of two connection surfaces per connection area is disadvantageous.
All the methods according to the prior art also have the disadvantage that a bending of the free ends of the rods, can bring their faces to be connected out of parallelism and thus impede a friction heating and plasticization of the material close the surface across the entire surface.